Ook fijn om weten:

In the next version of ASP.NET, the concept of the master page will be introduced. A master page is a distinct file referenced at the application level, as well as at the page level, that contains the static layout of the page. Regions that each derived page can customize are referenced in the master page with a special placeholder control. A derived page is simply a collection of blocks the run time will use to fill the holes in the master. Master pages in the next version of ASP.NET are orthogonal to true visual inheritance. The contents of the master, in fact, are merged into the derived page rather than serving as a base class for the derived page.

Dus ondertussen blijft het fiedelen met Pages en Inherits en <asp:placeholder>s.